SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '57e0c2692c3c1785b16f06353a1ccb4c555fb2941a64f4621f44c2be1d8b3ebc' 
  AND token = '7Z6Mc/vON2Md1vfiMLBvku4zUzynO9Mk4jgxfBNdLUo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

Explain
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE Impossible WHERE noticed after reading const tables