SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '28f11972bbd7c9129e5f621bfc4278a4430ebeb9ba3960c29f2804b1ed3645ac' 
  AND token = 'T9nKHUTvcNrvYE8gMaOQcjDDFMg2UfTOdA3P43UPlY0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00013

JSON explain

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