SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9481c449e00746bc93bac6e70ff934d723264f4fc053ce661d0f1578852a6350' 
  AND token = 'a4VjtoTzKlevPefbDB3yMa1ZedqzfsFBhcjj/xZIgAc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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