SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cc3639fa0388cfccb7c32197c5f16736fa50f9458658c654ddf2c28ce45c5305' 
  AND token = 'PPzXmQ5DHHbGOxrHLhNPHRrxyDGlVPRZZjEnXn6VIUk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00063

JSON explain

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