SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b306c9cf4755c7701276ee8a8680f32afd8674f7b07879286260dee0f4903779' 
  AND token = '18zCKKpXGNTCkcY4T/W3km5MOVw4nr/g+/CVPLUN+oA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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