SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c75a594bbd5b0d1365dc83948dadcfeb6a67acf7dbf65488738d21789111dbc5' 
  AND token = 'wNuo7k5dScAXEVR7uX+7lPHwIDCLTWotdiMpyVQmH6s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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