SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9ec0ab13f4ab24402302f3030ebcf81f0394a4f181911fa3c2dfeeffacab9849' 
  AND token = 'z4jThHWsbeLND1w2j2ZHc3fsdTchr5zjoL8bAd5UUIc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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