SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e127560508012fc4bfda7c723527a03e3f9f6e7a82d66f5c7388a4e586ca8fb3' 
  AND token = 'pLezZYOElGMIhwN2GEVyVgjIwW9VV5lvhBQNbQDlj14=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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