SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4c507939c6598e3277f720275137e718d59ce56e7d34f0312cee6c5b2b9013c8' 
  AND token = 'VKBQ0mEXN+h4AdbocyvV3asghP7+tr8GSeKFChMf1UI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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