SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3c41855dd258d8389c6d603fdb113549d7693d659eb87ac22e0ee7d463b3386d' 
  AND token = 'yLeHo2TnlCIrXgWM9ctRstTCv+f1rorPzMSV22LlQzk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00053

JSON explain

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