SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '585f9994da7d75f4621991fe727e72e4850b9c29072eed5b4616b039209c9908' 
  AND token = 'TgsNsUPdoZMxYamcWRDZVCGTH6om1h8E3JX6MzHY6Z8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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