SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ba8321635055cdc6ba1fd135435a4c75cfdcc95615cfd3fd99ff51e712f1e06a' 
  AND token = 'tYG4ztBqQ0EUBkXFKehB5psaZq+ADEoOcmzB+yTxug8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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