SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '440998f7360da954cdf3549ce3cfd15e506c8be9d160ec20e01af571502d9596' 
  AND token = 'xdZEnXOAh7R6IphIzeUuJ1ACihqVWHi7C9mWS21MWc4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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