SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '27d0723028ed4e23421f44c717819e4a7a42cd79f92377b25526556e7ba8af98' 
  AND token = 'QZdaVVVTWzMdZYYl5AJ6cfKZZq7PYB/MoHMNZsOLYCU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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