SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5f877f74ad0c840ea31341d52a1ba2e56c12101ddf0a8a57cd5dff0cbe441520' 
  AND token = 'Jsxo0F5tCRxOzvhE0c5SHoXOtfkrCcThVuFQkmNrXhM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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