SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9476d6fcae44419040784ef4bcbebf35ccd01a6bf76ceb11530d920e9476b147' 
  AND token = 'tBymLHhPtToe7wySt8CUOCsoeBm3MlHmmboATUsS3hY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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