SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '47ce011c6f86545538e95365ac5685a4fe0ed4729d409893b5bf6a023ade1599' 
  AND token = '19QuwoeJaxcsfmfu1zF4rnIsFS4h7ztXdVuAZw66rGA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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