SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '39a2649f9bd3d17c53daadfc8568aaf3fcba98fbc57f6f4c082f5548bb86acf5' 
  AND token = 'vj5JkSEqYDU4zfVQc0aFBQpLLHyaTvYdqjQo4N/36hA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

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