SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b694b042426a307e9d0501977f3fc51d63964cf37a941e2021752b4021f2895d' 
  AND token = 'X8+mGmwfnWhqKCimOfCbFGaPepzQSch1Phsn+DFvluM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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