SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2140afc7627f30e8ee69238603f6875d2785176b9b2768524fa5be2ec835330e' 
  AND token = '9rXlAdFvpcmAAwnXolaOMoKJy/qUGVh99nGrM4l1onw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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