SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd05f4b5691cdc7a43643481734b255615f0ab18eaedb039fec71809115f8b7e7' 
  AND token = 'mqEVhHfIm+IifGpxP+/7gqabuRD0smj6vVutxHGvdIA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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