SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c25d055a60496e6ca774a1406b578f9489e89418226d49528646322f187cff9f' 
  AND token = 'BpJuquKbUzv1HU9NxWD6OTNwT7IXCwrJi9c+gTPTBr0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00067

JSON explain

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