SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '821015b6babcc14097bc12c7a80b6f7a897a1ea1bc863efaa62730d8316480b0' 
  AND token = 'geJS6bBhJAR6uDhmOkXgzlZ6IQ+mpkJkfDqe68Ac6n0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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