SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'da698042b45142e649866e3202d090fca9235751436c776d70c180060e33bdc9' 
  AND token = '5Kb8UoduOfD43Ze6xD0kFdkRuwmM6EfselhbvIffkP8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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