SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '20763f878a9ae6b557c0cbf846f613d2010a15451cf882a7f6da298bd1fc664b' 
  AND token = 'P/IprC7WhAlYpc1UXpvbIkU0RcmDVjY3pyBbiVNAY9c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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