SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ff3115c5f3b14bdac86569629aa0f34d5498e43e351cbe1befc5477416330bff' 
  AND token = '4HXigVJFC64VBPp/0J4EH7QI2cyvrLCjozK3R8/PhXA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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