SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dbc7d390cca93140a0af8b4c227884f09c810c9ad9b202dbbe31ebe5f0e78105' 
  AND token = 'DatXeuF/UBfdsjrA8vnbZMjvXEsLRZsvg4/mb9Eimng=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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