SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'd58555a2bf564d17aab06c91664340f04bb7cad68fb9889d6a41b30e94cd2529' 
  AND token = 'KDvrCeEzOQumHUrXTSzBoPvDL/upMeAECz/DL2heWGc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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