SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f1b4df6031676091610bd4f4d482e62864cc525fb664684461523c6951b6d538' 
  AND token = 'H56Jpv5AvEgg8bWMBpK8FqTrAyY4j7YNfe02f9BQZNk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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