SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7eaeeda4967839942fe10cc8d28a7140aeb54de72bd5d1fd7892015e79e574f0' 
  AND token = 'CbSnqKiHCw0FOjw0D4PnxMNmOjiGx75gmCY0TK1i5VU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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