SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7ab4cb310b7deb8dd567611c1b3a1724e5a559145d73787981ce28c858324f94' 
  AND token = 'YtOqxrvGLsXcMLlfR2KvRwtsMTAe2EgtuCbzPRGbDYk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}