The LOCATE() function of MySQL returns the position of the first occurrence of a substring in a string. Use can use this function to find if your string/substring is present in a column. Here is the SQL query you can try:
SELECT * FROM tableName WHERE LOCATE(yourString, columnName) > 0
If your substring starts from the very first position in the string, you can try the following SQL code:
SELECT columnName, LOCATE(yourString, columnName) as positionFound FROM tableName