SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b7029e3603580a55fbfa14a220b81223fdf753812dbcb144bcddc61c4c5a28f9' 
  AND token = 'HuVCJrUQGyH0ofJ0aTR2ykHdI67xydSRzEBa40w+mI4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}