SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '84fde96b5cd22e30fbb596637d41511bc4cb797f71c8f44be442a800ec6bd1f8' 
  AND token = 'YvPv2UmiSpdKv9O2uLISMpdinFClncWPSZhNgQPIekw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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