SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '043d5960f2071ef7727383884619ae4cefe4e5ea759a666f1971a0e374402763' 
  AND token = 'FIYZxGoiXO2+YgiVuecaZVdzhjh5cg79iAq2CfuUQJY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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