SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c4972807c7e4ad846193f260aec9c1e3fe5fc20e5c05799032e89202d9a721fd' 
  AND token = 'amPn3/uK9Oy2btp5AWTMzhPv6oo6OLK48ezLNUDfkdg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

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