SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1f950f6aa689ec87373d065c3935126e35ffb93b710584e1dca16d083044595c' 
  AND token = 'lLvV1eIDOOwtuheJsIz3n5f1uux2PsHdsl80mkmSzYs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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