SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4849963c588315b5d75eb500458af0420ab9678e669d5828590108aa98d1fe6d' 
  AND token = 'w0ZRHeAhaS968s7jr98DuAQNfx2BdpJF+ofmwxEA234=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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