SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd4c1cbcdce75744dc85a52c0944ba6d19660c90f8ca4a297fa4ff94df3baf088' 
  AND token = 'mT9dd0r5wAxvJXOyiRhyIvoQi2dcmu2DH0jRzEeM6WI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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