SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4fc30d4b13e735becce5993cbb126cb9f4980e815e239ddb292a3917ee81ab08' 
  AND token = 'EnpEmMIvWcTDL9DqPnFGEwe3bvqvKzdyCfRJwE8KVp8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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