SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e99ef16733d98ebb49ced59a3dea636f2dd840fbeb174050de607d913586c5b7' 
  AND token = 'ffQq0OVM4wgTVdVubFaVzKLEAtKeKz1LPovGp4oOWww=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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