SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '66c259d2e0159a4a2fd5be7af0504178f33046881fabdf501ae1aaf74e703c94' 
  AND token = 'WXj2BqBu+PgAVlz1C9PEwp46HrMrxWD5R5NSmZHlL6I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00058

JSON explain

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