SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c225d4be951d72f8249cf5fd51baccbda66d655e0ba3f61f40b96043fd0e6d03' 
  AND token = 'gkKWmzV+DKdJfjM4KEIbhsK9Uuvcxwynh1UMSCOz3oA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}