SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4c3f7ff05de03d93b01aa420166a4ce5558a099e9ba9c362865587a125016990' 
  AND token = 'k2RaZi5PNo/uCeqC6WfgfHgUbvyppYzfidGVK+Z7HWk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00049

JSON explain

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