SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '870d2aeddb67c24f259206159df65437dbca9537e7df6792616c772e8e8b9f30' 
  AND token = 'NwKmB/6bwpaXQ4z52Xr9lOmAsk38Knsml4yQHnqZ5L4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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