SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b455081197f5c145008d475ac3d98dcacdf12ab6e85c5f35136d0dbd27a8560d' 
  AND token = 'vFfTrBsQXu7VLG5eDSNedHfVdhtpmWPvwSI5K/23WhM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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