SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '01c604aaab0e8ee41ea5db658940a5d612275a3e95d22f092d968e8edcde6953' 
  AND token = 'QTmn/pmaoDfHo+wweShTnza12h7DgEse+TFBscBVCTw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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