SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '36fad39fcb1e2f0c4204f761afe3f90814d080763e4aa051ce8d245afe2cab28' 
  AND token = 'KObENCie8carqQqkyd3b5nZg/1tat8g+U/C7Ky2vUSI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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