SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2878dfc3dd56299b4d842dbec14de47309765334916c421e829cd1abea3eea2e' 
  AND token = 'l3V0Xyl22XQA5c7T/1hCcwY7FrUCM+4ogW++ZxmMq1A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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