SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '75a1844c67f212383b2df162443f4bf2e217a298bf7249182e807d496f41948c' 
  AND token = '5bSqz/rUERV/wU4OdKPLsQOXX1hn6pkMZ9m0UOylVU0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00014

JSON explain

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