SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '66d04c54747ab9dff6201cccfb9740fcba01e304f64f3a36029e54d47c828ac8' 
  AND token = 'cdMkX8oWTnrOVt0dabbh3rDawOpRhBh42mmY0rbPH0I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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