SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '75578f1ab5f714fc1105292fbd2eb2fb3bd47dab50b20a738289182b233bfcae' 
  AND token = 'WQm1bkscqjeMjaRFtz6dYDE3uF8ISpk3pYj4iH/vDlY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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