SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ef027741ffbeb0d1497555b2a9f9d1380ee7297d6da9af4c3c54c2180c5634d0' 
  AND token = 'mSOCgH/Z/1v9h+YwkpM42ZHwNiTm2ECBHw3QiA8Im+k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

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