SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8c3d83c2e30689a5269ab59119906ede843a0b250161a99d3d4e82451a50d7af' 
  AND token = 'LnS+OGVI5i+U6oUZ9axYgWJWVyXh0GGOKMr2VkU9ZHE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}