SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4848314b73b13473731c0821dfba2e79a527c38c828490a2da5785b803afa3f8' 
  AND token = 'JmrJACeOlLQynVDpCKizut+TeHkcaStdqw/1c8RDxbM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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