SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '28125d7b1b17f2799ab102cd146bf66556a189568e90054f477867c70ac294dc' 
  AND token = 'rKYkWV4HvvpaYqxO+2HFOzThQUBcj+7FVEODD+ShQBg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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