SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b9e743744abf3e755c4eea1713afbca9318049f4362bce1ace66a4a9fb9c3371' 
  AND token = 'QGvIpNQgMrcPDeiXXsGBI2RwHOSeBISxp0W1ZU8comY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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