SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1ab781b8bff20cf9f6d3cdcc65abbeeb74361c7e641da6d6dcb7a1801a48d364' 
  AND token = 'trzI6FYkENNzfZkvIZRJGmBH+IoKrO+EmWlNQIUiVpE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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