SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '79803f23f17ce9fa0be20071316767de70fefdf45d93a870998d63808d156c2a' 
  AND token = 'dmmCI7m957aYeo1bzUGMgtv/2BTBYYxe9To0vLKEPC4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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