SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd6611985441c993985c54f1dedace21686180a4f86c9573c4ea549affa0d190a' 
  AND token = 'UQHw7IsfV6eC6DVeVtkTh3YTGqhmP2Bmgs8Vdi6vbNM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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