SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'db909924c47b30a26d611563eb3a300db0304adf0a18a77da8106f09d7048ee9' 
  AND token = 'w3rUquJ8aXGfAzPXZ9FLvSxiopIqdcB50BcuCDZ2uyU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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