SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c745266fa3da9db98d7c0ffbee17915c5172b4f84aa93fe03140ad7bde9930be' 
  AND token = 'W8TbVyCf10GIu5cL+QyGpgunjCtoJFVh3GXgv/pzsVM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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