SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5a5605ac1171a5422aefd684c40318050ee613adbd8d5e8e8f889da6a389481a' 
  AND token = '8zEtViYGLz0FsKkOy82oM6gt8xPrJfNQrEifa4+1i64=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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