SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b8551cbeea8d8d6abf3a54313a2d88fd1de0400d33bb14ecfa9e22e941658a71' 
  AND token = 'uM7l5PvQuBb/Oo/Bdd5YszLuhjthd9ZJah4ziQV54mQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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